The present invention relates to a motor and a disk drive apparatus including the motor.
In recent years, a motor in which current paths are altered electronically by using a number of transistors has been used widely in office automation apparatuses and audio-visual apparatuses. In other words, optical disk drive apparatuses (such as DVD apparatuses, CD apparatuses, etc.), magnetic disk drive apparatuses (such as HDD apparatuses, FDD apparatuses, etc.) and the like, include this kind of motor.
FIG. 35 shows a conventional motor, and the operation of the motor will be described below. A rotor 2011 has a field part formed by a permanent magnet. In a position detector 2041, three position sensors detect the magnetic field of the field part of the rotor 2011. The position detector 2041 produces two sets of three-phase voltage signals, Kp1, Kp2 and Kp3, and Kp4, Kp5 and Kp6, from the three-phase output signals of the three position sensors responding with the rotation of the rotor 2011. A first distributor 2042 produces three-phase low-side signals Mp1, Mp2 and Mp3 responding with the voltage signals Kp1, Kp2 and Kp3, and controls the activation of the low-side NPN-type bipolar power transistors 2021, 2022 and 2023. A second distributor 2043 produces three-phase high-side signals Mp4, Mp5 and Mp6 responding with the voltage signals Kp4, Kp5 and Kp6, and controls the activation of the high-side PNP-type bipolar power transistors 2025, 2026 and 2027. Hence, three-phase drive voltages are supplied to windings 2012, 2013 and 2014.
In this conventional configuration, power losses at the power transistors are large, whereby the power efficiency of the motor is significantly low. The NPN-type bipolar power transistors 2021, 2022 and 2023 and the PNP-type bipolar power transistors 2025, 2026 and 2027 supply drive voltages to the windings 2012, 2013 and 2014 by controlling voltage drops between the emitters and the collectors thereof in an analogue manner responding with the output signals of the three position sensors. A residual voltage in each power transistor is large, and a large power loss and heat generation are caused by the product of the residual voltage and the drive current supplied to each winding. As a result, the power efficiency of the motor is low, and the power consumption of the disk drive apparatus including the motor is large. In addition, the power loss increases the disk temperature at the disk drive apparatus, thereby increasing bit errors during recording and reproduction of information on a disk.
The specification of U.S. Pat. No. 5,982,118 discloses a motor wherein power transistors are subjected to PWM operation (PWM: Pulse Width Modulation) by using the outputs of two sensor to reduce power consumption. However, in the motor configurations in accordance with the above-mentioned conventional example shown in FIG. 35 and the specification of U.S. Pat. No. 5,982,118, two or three position sensors are included to detect the rotational position of the rotor. Hence, space, wiring, etc. are required for the installation of the position sensors, thereby making the configurations complicated and raising the cost thereof.
The specifications of U.S. Pat. No. 5,122,715 and U.S. Pat. No. 5,473,232 disclose motors wherein the terminal voltages of the windings are detected and the current paths to the windings are altered responding with the timing of the detection. In the motor configuration described in the specification of U.S. Pat. No. 5,122,715, the width of activation is 120 degrees, whereby vibration and acoustic noise are significant. In addition, the motor configuration is complicated due to use of a switching regulator. In the motor configuration described in the specification of U.S. Pat. No. 5,473,232, power transistors are subjected to PWM operation to reduce power losses. However, the width of activation for each power transistor is 120 degrees, whereby vibration and acoustic noise are significant. Furthermore, in the motor configuration described in the specification of U.S. Pat. No. 5,473,232, the detection timing of the terminal voltages of the windings is apt to fluctuate because of the PWM operation. Hence, when the rotational speed of the rotor is controlled by a detected pulse signal responding with the terminal voltages of the windings, fluctuation of the rotational speed of the rotor occurs owing to the timing fluctuation of the detected pulse signal.
In magnetic disk drive apparatuses, such as HDD apparatuses, and optical disk drive apparatuses, such as DVD apparatuses, speed fluctuation (jitter) must be minimized to stably carry out recording and/or reproduction on a high-density disk. However, when power transistors are subjected to PWM operation, very large high-frequency switching noise occurs, thereby causing a large timing fluctuation of the detected pulse signal. Hence, the reliability of the recording and/or reproduction of the disk drive apparatus lowers significantly. It is thus difficult to subject the power transistors to PWM operation.
The object of the present invention is to provide a motor and a disk drive apparatus including the motor wherein the above-mentioned problems have been solved individually or concurrently.
A motor in accordance with one aspect of the present invention comprises:
a rotor having a field part which generates field fluxes;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means, including two output terminals, for supplying a DC voltage;
power supplying means having Q first power transistors and Q second power transistors, each of said Q first power transistors forming a current path between first output terminal side of said voltage supplying means and one of said Q-phase windings, and each of said Q second power transistors forming a current path between second output terminal side of said voltage supplying means and one of said Q-phase windings;
voltage detecting means for producing a detected pulse signal which responds with terminal voltages of said Q-phase windings;
phase detecting means for producing a phase pulse signal which responds with terminal voltages of said Q-phase windings;
state shifting means for shifting a holding state from one state to at least one other state in sequence responding with said detected pulse signal of said voltage detecting means;
activation control means for controlling active periods of said Q first power transistors and said Q second power transistors responding with said holding state of said state shifting means;
commanding means for producing a command signal which responds with said phase pulse signal of said phase detecting means; and
switching operation means for causing at least one power transistor among said Q first power transistors and said Q second power transistors to perform high-frequency switching responding with said command signal;
and that
said activation control means causes each of said active periods of said Q first power transistors and said Q second power transistors to become larger than the period of 360/Q electrical degrees,
said switching operation means produces a high-frequency switching pulse signal which responds with said command signal and switches said at least one power transistor responding with said switching pulse signal,
and
said phase detecting means includes:
slant producing means for producing a slant voltage signal at a terminal of a capacitor, said slant voltage signal responding intermittently with a voltage difference between one of the power supplying terminal voltages and the common terminal voltage of said Q-phase windings during sampling periods and having substantially a voltage slant during at least one of the rest periods except said sampling periods, and
phase pulse producing means for producing said phase pulse signal by comparing said slant voltage signal with a reference voltage.
With this configuration, the switching operation means cause the power transistors of the power supplying means to perform high-frequency switching. Hence, the power losses of the power transistors of the power supplying means are reduced remarkably, and heat generation at the motor is reduced significantly. In addition, the voltage detecting means, the state shifting means and the activation control means produce the detected pulse signal responding with the terminal voltages of the windings and cause the rotor to rotate in a predetermined direction responding with the detected pulse signal. Therefore, no position sensor is necessary, and the configuration of the motor is simplified. Furthermore, the active periods of the first and second power transistors are set so as to be larger than the period of an electrical angle of 360/Q degrees, whereby two of the power transistors are activated simultaneously during the alteration of current paths. Hence, the alteration of the current paths becomes smooth, and the pulsation of the generated drive force becomes small, whereby the motor has low vibration and low acoustic noise. Still further, the slant voltage signal at the terminal (or across the terminals) of the single capacitor intermittently responds with the voltage difference between one of the power supplying terminal voltages and the common terminal voltage of the Q-phase windings during the sampling periods. The slant voltage signal has the voltage slant during at least one of the rest periods other than the sampling periods. As a result, it is possible to produce accurately the slant voltage signal which nearly corresponds to the voltage difference between one of the power supplying terminal voltages and the common terminal voltage. The phase detecting means selects one of the power supplying terminal voltages responding with the operation state of the activation control means, for example. Since the slant voltage signal intermittently responds with the voltage difference between one of the power supplying terminal voltages and the common terminal voltage, the slant producing means can produce the slant voltage signal having an accurate voltage slant at the terminal of the single capacitor. Since the phase pulse signal responds with the slant voltage signal, the phase pulse signal is free from the influence of the switching of the power transistors. Therefore the phase pulse signal changes at accurate timing. The commanding means produces the command signal responding with the rotational speed of the rotor by using the phase pulse signal. The switching operation means causes at least one of the power transistors to perform high-frequency switching responding with the command signal. Hence, the rotational speed of the rotor can be controlled accurately. As a result, a motor with low power consumption, low vibration, low acoustic noise and low fluctuation of the rotational speed can be realized at low cost.
A motor in accordance with another aspect of the present invention comprises:
a rotor having a field part which generates field fluxes;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means, including two output terminals, for supplying a DC voltage;
power supplying means having Q first power transistors and Q second power transistors, each of said Q first power transistors forming a current path between first output terminal side of said voltage supplying means and one of said Q-phase windings, and each of said Q second power transistors forming a current path between second output terminal side of said voltage supplying means and one of said Q-phase windings;
phase detecting means for producing a phase pulse signal which responds with terminal voltages of said Q-phase windings;
state shifting means for shifting a holding state from one state to at least one other state in sequence responding with said phase pulse signal of said phase detecting means;
activation control means for controlling active periods of said Q first power transistors and said Q second power transistors responding with said holding state of said state shifting means;
commanding means for producing a command signal which responds with said phase pulse signal of said phase detecting means; and
switching operation means for causing at least one power transistor among said Q first power transistors and said Q second power transistors to perform high-frequency switching responding with said command signal;
and that
said activation control means causes each of said active periods of said Q first power transistors and said Q second power transistors to become larger than the period of 360/Q electrical degrees,
said switching operation means produces a high-frequency switching pulse signal which responds with said command signal and switches said at least one power transistor responding with said switching pulse signal,
and
said phase detecting means includes:
slant producing means for producing a slant voltage signal at a terminal of a capacitor, said slant voltage signal responding intermittently with a voltage difference between one of the power supplying terminal voltages and the common terminal voltage of said Q-phase windings during sampling periods and having substantially a voltage slant during at least one of the rest periods except said sampling periods, and
phase pulse producing means for producing said phase pulse signal by comparing said slant voltage signal with a reference voltage.
With this configuration, the switching operation means cause the power transistors of the power supplying means to perform high-frequency switching. Hence, the power losses of the power transistors of the power supplying means are reduced remarkably, and heat generation at the motor is reduced significantly. In addition, the phase detecting means, the state shifting means and the activation control means produce the phase pulse signal responding with the terminal voltages of the windings and cause the rotor to rotate in a predetermined direction responding with the phase pulse signal. Therefore, no position sensor is necessary, and the configuration of the motor is simplified. Furthermore, the active periods of the first and second power transistors are set so as to be larger than the period of an electrical angle of 360/Q degrees, whereby two of the power transistors are activated simultaneously during the alteration of current paths. Hence, the alteration of the current paths becomes smooth, and the pulsation of the generated drive force becomes small, whereby the motor has low vibration and low acoustic noise. Still further, the slant voltage signal at the terminal (or across the terminals) of the single capacitor intermittently responds with the voltage difference between one of the power supplying terminal voltages and the common terminal voltage of the Q-phase windings during the sampling periods. The slant voltage signal has the voltage slant during at least one of the rest periods other than the sampling periods. As a result, it is possible to produce accurately the slant voltage signal which nearly corresponds to the voltage difference between one of the power supplying terminal voltages and the common terminal voltage. The phase detecting means selects one of the power supplying terminal voltages responding with the operation state of the activation control means, for example. Since the slant voltage signal intermittently responds with the voltage difference between one of the power supplying terminal voltages and the common terminal voltage, the slant producing means can produce the slant voltage signal having an accurate voltage slant at the terminal of the single capacitor. Since the phase pulse signal responds with the slant voltage signal, the phase pulse signal is free from the influence of the switching of the power transistors. Therefore the phase pulse signal changes at accurate timing. The commanding means produces the command signal responding with the rotational speed of the rotor by using the phase pulse signal. The switching operation means causes at least one of the power transistors to perform high-frequency switching responding with the command signal. Hence, the rotational speed of the rotor can be controlled accurately. As a result, a motor with low power consumption, low vibration, low acoustic noise and low fluctuation of the rotational speed can be realized at low cost.
A motor in accordance with still another aspect of the present invention:
a rotor having a field part which generates field fluxes;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means, including two output terminals, for supplying a DC voltage;
power supplying means having plural power transistors, said plural power transistors supplying said Q-phase windings with bi-directional currents from said voltage supplying means;
phase detecting means for producing a phase pulse signal which responds with terminal voltages of said Q-phase windings;
activation operation means for controlling active periods of said plural power transistors responding with terminal voltages of said Q-phase windings;
commanding means for producing a command signal which responds with said phase pulse signal of said phase detecting means; and
switching operation means for causing at least one power transistor among said plural power transistors to perform high-frequency switching responding with said command signal;
and that
said activation operation means causes each of said active periods of said plural power transistors to become larger than the period of 360/Q electrical degrees,
said switching operation means produces a high-frequency switching pulse signal which responds with said command signal and switches said at least one power transistor responding with said switching pulse signal,
and
said phase detecting means includes:
slant producing means for producing a slant voltage signal at a terminal of a capacitor, said slant voltage signal responding intermittently with a voltage difference between one of the power supplying terminal voltages and the common terminal voltage of said Q-phase windings during sampling periods and having substantially a voltage slant during at least one of the rest periods except said sampling periods, and
phase pulse producing means for producing said phase pulse signal responding with said slant voltage signal.
With this configuration, the switching operation means cause the power transistors of the power supplying means to perform high-frequency switching. Hence, the power losses of the power transistors of the power supplying means are reduced remarkably, and heat generation at the motor is reduced significantly. In addition, the activation operation means control the active periods of the power transistors responding with the terminal voltages of the windings and cause the rotor to rotate in a predetermined direction. Therefore, no position sensor is necessary, and the configuration of the motor is simplified. Furthermore, the active periods of the power transistors are set so as to be larger than the period of an electrical angle of 360/Q degrees, whereby two of the power transistors are activated simultaneously in the alteration of current paths. Hence, the alteration of the current paths becomes smooth, and the pulsation of the generated drive force becomes small, whereby the motor has low vibration and low acoustic noise. Still further, the slant voltage signal at the terminal (or across the terminals) of the single capacitor intermittently responds with the voltage difference between one of the power supplying terminal voltages and the common terminal voltage of the Q-phase windings during the sampling periods. The slant voltage signal has the voltage slant in at least one of the rest periods other than the sampling periods. As a result, it is possible to produce accurately the slant voltage signal which nearly corresponds to the voltage difference between one of the power supplying terminal voltages and the common terminal voltage. The phase detecting means selects one of the power supplying terminal voltages responding with the operation state of the activation operation means, for example. Since the slant voltage signal intermittently responds with the voltage difference between one of the power supplying terminal voltages and the common terminal voltage, the slant producing means can produce the slant voltage signal having an accurate voltage slant at the terminal of the single capacitor. Since the phase pulse signal responds with the slant voltage signal, the phase pulse signal is free from the influence of the switching of the power transistors. Therefore the phase pulse signal changes at accurate timing. The commanding means produces the command signal responding with the rotational speed of the rotor by using the phase pulse signal. The switching operation means causes at least one of the power transistors to perform high-frequency switching responding with the command signal. Hence, the rotational speed of the rotor can be controlled accurately. As a result, a motor with low power consumption, low vibration, low acoustic noise and low fluctuation of the rotational speed can be realized at low cost.
A motor in accordance with further aspect of the present invention:
a rotor having a field part which generates field fluxes;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means, including two output terminals, for supplying a DC voltage;
power supplying means having plural power transistors, said plural power transistors supplying said Q-phase windings with bi-directional currents from said voltage supplying means;
phase detecting means for producing a phase pulse signal which responds with terminal voltages of said Q-phase windings;
activation operation means for controlling active periods of said plural power transistors responding with terminal voltages of said Q-phase windings;
commanding means for producing a command signal which responds with said phase pulse signal of said phase detecting means; and
switching operation means for causing at least one power transistor among said plural power transistors to perform high-frequency switching responding with said command signal;
and that
said activation operation means causes each of said active periods of said plural power transistors to become larger than the period of 360/Q electrical degrees,
said switching operation means produces a high-frequency switching pulse signal which responds with said command signal and switches said at least one power transistor responding with said switching pulse signal,
and
said phase detecting means includes:
slant producing means for producing a first voltage signal at a terminal of a first capacitor which intermittently responds with one of the power supplying terminal voltages of said Q-phase winding means, and producing a second voltage signal at a terminal of a second capacitor which intermittently responds with the common terminal voltage of said Q-phase windings during sampling periods and has substantially a voltage slant during at least one of the rest periods except said sampling periods,
and
phase pulse producing means for producing said phase pulse signal by comparing said first voltage signal with said second voltage signal.
With this configuration, the switching operation means cause the power transistors of the power supplying means to perform high-frequency switching. Hence, the power losses of the power transistors of the power supplying means are reduced remarkably, and heat generation at the motor is reduced significantly. In addition, the activation operation means control the active periods of the power transistors responding with the terminal voltages of the windings and cause the rotor to rotate in a predetermined direction. Therefore, no position sensor is necessary, and the configuration of the motor is simplified. Furthermore, the active periods of the power transistors are set so as to be larger than the period of an electrical angle of 360/Q degrees, whereby two of the power transistors are activated simultaneously in the alteration of current paths. Hence, the alteration of the current paths becomes smooth, and the pulsation of the generated drive force becomes small, whereby the motor has low vibration and low acoustic noise. Still further, the first voltage signal intermittently responds with one of the power supplying terminal voltages of the Q-phase windings. The second voltage signal intermittently responds with the common terminal voltage of the Q-phase windings during the sampling periods and has the voltage slant during at least one of the rest periods other than the sampling periods. The phase detecting means selects one of the power supplying terminal voltages responding with the operation state of the activation operation means, for example. Since the second voltage signal having the voltage slant responds with the common terminal voltage, the second voltage signal has a relatively intermediate level. It is thus easy to add the accurate voltage slant to the second voltage signal. Since the phase pulse signal responds with the comparison result between the first voltage signal and the second voltage signal, the phase pulse signal is free from the influence of the switching of the power transistors. Therefore the phase pulse signal changes at accurate timing. The commanding means produces the command signal responding with the rotational speed of the rotor by using the phase pulse signal. The switching operation means causes at least one of the power transistors to perform high-frequency switching responding with the command signal. Hence, the rotational speed of the rotor can be controlled accurately. As a result, a motor with low power consumption, low vibration, low acoustic noise and low fluctuation of the rotational speed can be realized at low cost.
A disk drive apparatus in accordance with one aspect of the present invention comprises:
head means for at least reproducing a signal from a disk or recording a signal on said disk;
processing means for at least processing an output signal from said head means and outputting a reproduced signal, or processing a signal and outputting a recording signal into said head means;
a rotor, having a field part which generates field fluxes, for driving directly said disk;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means, including two output terminals, for supplying a DC voltage;
power supplying means having Q first power transistors and Q second power transistors, each of said Q first power transistors forming a current path between first output terminal side of said voltage supplying means and one of said Q-phase windings, and each of said Q second power transistors forming a current path between second output terminal side of said voltage supplying means and one of said Q-phase windings;
voltage detecting means for producing a detected pulse signal which responds with terminal voltages of said Q-phase windings;
phase detecting means for producing a phase pulse signal which responds with terminal voltages of said Q-phase windings;
state shifting means for shifting a holding state from one state to at least one other state in sequence responding with said detected pulse signal of said voltage detecting means;
activation control means for controlling active periods of said Q first power transistors and said Q second power transistors responding with said holding state of said state shifting means;
commanding means for producing a command signal which responds with said phase pulse signal of said phase detecting means; and
switching operation means for causing at least one power transistor among said Q first power transistors and said Q second power transistors to perform high-frequency switching responding with said command signal;
and that
said activation control means causes each of said active periods of said Q first power transistors and said Q second power transistors to become larger than the period of 360/Q electrical degrees,
said switching operation means produces a high-frequency switching pulse signal which responds with said command signal and switches said at least one power transistor responding with said switching pulse signal,
and
said phase detecting means includes:
slant producing means for producing a slant voltage signal at a terminal of a capacitor, said slant voltage signal responding intermittently with a voltage difference between one of the power supplying terminal voltages and the common terminal voltage of said Q-phase windings during sampling periods and having substantially a voltage slant during at least one of the rest periods except said sampling periods, and
phase pulse producing means for producing said phase pulse signal by comparing said slant voltage signal with a reference voltage.
With this configuration, the switching operation means cause the power transistors of the power supplying means to perform high-frequency switching. Hence, the power losses of the power transistors of the power supplying means are reduced remarkably, and heat generation at the disk drive apparatus is reduced significantly. In addition, the voltage detecting means, the state shifting means and the activation control means produce the detected pulse signal responding with the terminal voltages of the windings and cause the rotor to rotate in a predetermined direction responding with the detected pulse signal. Therefore, no position sensor is necessary, and the configuration of the disk drive apparatus is simplified. Furthermore, the active periods of the first and second power transistors are set so as to be larger than the period of an electrical angle of 360/Q degrees, whereby two of the power transistors are activated simultaneously in the alteration of current paths. Hence, the alteration of the current paths becomes smooth, and the pulsation of the generated drive force becomes small, thereby reducing variation and acoustic noise of the disk remarkably. Still further, the slant voltage signal at the terminal (or across the terminals) of the single capacitor intermittently responds with the voltage difference between one of the power supplying terminal voltages and the common terminal voltage of the Q-phase windings during the sampling periods. The slant voltage signal has the voltage slant during at least one of the rest periods other than the sampling periods. As a result, it is possible to produce accurately the slant voltage signal which nearly corresponds to the voltage difference between one of the power supplying terminal voltages and the common terminal voltage. The phase detecting means selects one of the power supplying terminal voltages responding with the operation state of the activation control means, for example. Since the slant voltage signal intermittently responds with the voltage difference between one of the power supplying terminal voltages and the common terminal voltage, the slant producing means can produce the slant voltage signal having an accurate voltage slant at the terminal of the single capacitor. Since the phase pulse signal responds with the slant voltage signal, the phase pulse signal is free from the influence of the switching of the power transistors. Therefore the phase pulse signal changes at accurate timing. The commanding means produces the command signal responding with the rotational speed of the rotor by using the phase pulse signal. The switching operation means causes at least one of the power transistors to perform high-frequency switching responding with the command signal. Hence, the rotational speed of the disk can be controlled accurately, thereby improving reliability during recording and/or reproduction. As a result, a disk drive apparatus with low power consumption, low temperature increase, low disk vibration and low disk noise, suited for recording and/or reproduction on a high-density disk can be realized at low cost.
A disk drive apparatus in accordance with another aspect of the present invention comprises:
head means for at least reproducing a signal from a disk or recording a signal on said disk;
processing means for at least processing an output signal from said head means and outputting a reproduced signal, or processing a signal and outputting a recording signal into said head means;
a rotor, having a field part which generates field fluxes, for driving directly said disk;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means, including two output terminals, for supplying a DC voltage;
power supplying means having Q first power transistors and Q second power transistors, each of said Q first power transistors forming a current path between first output terminal side of said voltage supplying means and one of said Q-phase windings, and each of said Q second power transistors forming a current path between second output terminal side of said voltage supplying means and one of said Q-phase windings;
phase detecting means for producing a phase pulse signal which responds with terminal voltages of said Q-phase windings;
state shifting means for shifting a holding state from one state to at least one other state in sequence responding with said phase pulse signal of said phase detecting means;
activation control means for controlling active periods of said Q first power transistors and said Q second power transistors responding with said holding state of said state shifting means;
commanding means for producing a command signal which responds with said phase pulse signal of said phase detecting means; and
switching operation means for causing at least one power transistor among said Q first power transistors and said Q second power transistors to perform high-frequency switching responding with said command signal;
and that
said activation control means causes each of said active periods of said Q first power transistors and said Q second power transistors to become larger than the period of 360/Q electrical degrees,
said switching operation means produces a high-frequency switching pulse signal which responds with said command signal and switches said at least one power transistor responding with said switching pulse signal,
and
said phase detecting means includes:
slant producing means for producing a slant voltage signal at a terminal of a capacitor, said slant voltage signal responding intermittently with a voltage difference between one of the power supplying terminal voltages and the common terminal voltage of said Q-phase windings during sampling periods and having substantially a voltage slant during at least one of the rest periods except said sampling periods, and
phase pulse producing means for producing said phase pulse signal by comparing said slant voltage signal with a reference voltage.
With this configuration, the switching operation means cause the power transistors of the power supplying means to perform high-frequency switching. Hence, the power losses of the power transistors of the power supplying means are reduced remarkably, and heat generation at the disk drive apparatus is reduced significantly. In addition, the phase detecting means, the state shifting means and the activation control means produce the phase pulse signal responding with the terminal voltages of the windings and cause the rotor to rotate in a predetermined direction responding with the phase pulse signal. Therefore, no position sensor is necessary, and the configuration of the disk drive apparatus is simplified. Furthermore, the active periods of the first and second power transistors are set so as to be larger than the period of an electrical angle of 360/Q degrees, whereby two of the power transistors are activated simultaneously in the alteration of current paths. Hence, the alteration of the current paths becomes smooth, and the pulsation of the generated drive force becomes small, thereby reducing vibration and acoustic noise of the disk remarkably. Still further, the slant voltage signal at the terminal (or across the terminals) of the single capacitor intermittently responds with the voltage difference between one of the power supplying terminal voltages and the common terminal voltage of the Q-phase windings during the sampling periods. The slant voltage signal has the voltage slant during at least one of the rest periods other than the sampling periods. As a result, it is possible to produce accurately the slant voltage signal which nearly corresponds to the voltage difference between one of the power supplying terminal voltages and the common terminal voltage. The phase detecting means selects one of the power supplying terminal voltages responding with the operation state of the activation control means, for example. Since the slant voltage signal intermittently responds with the voltage difference between one of the power supplying terminal voltages and the common terminal voltage, the slant producing means can produce the slant voltage signal having an accurate voltage slant across the terminals of the single capacitor. Since the phase pulse signal responds with the slant voltage signal, the phase pulse signal is free from the influence of the switching of the power transistors. Therefore the phase pulse signal changes at accurate timing. The commanding means produces the command signal responding with the rotational speed of the rotor by using the phase pulse signal. The switching operation means causes at least one of the power transistors to perform high-frequency switching responding with the command signal. Hence, the rotational speed of the disk can be controlled accurately, thereby improving reliability during recording and/or reproduction. As a result, a disk drive apparatus with low power consumption, low temperature increase, low disk vibration and low disk noise, suited for recording and/or reproduction on a high-density disk can be realized at low cost.
A disk drive apparatus in accordance with still another aspect of the present invention comprises:
head means for at least reproducing a signal from a disk or recording a signal on said disk;
processing means for at least processing an output signal from said head means and outputting a reproduced signal, or processing a signal and outputting a recording signal into said head means;
a rotor, having a field part which generates field fluxes, for driving directly said disk;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means, including two output terminals, for supplying a DC voltage;
power supplying means having plural power transistors, said plural power transistors supplying said Q-phase windings with bi-directional currents from said voltage supplying means;
phase detecting means for producing a phase pulse signal which responds with terminal voltages of said Q-phase windings;
activation operation means for controlling active periods of said plural power transistors responding with terminal voltages of said Q-phase windings;
commanding means for producing a command signal which responds with said phase pulse signal of said phase detecting means; and
switching operation means for causing at least one power transistor among said plural power transistors to perform high-frequency switching responding with said command signal;
and that
said activation operation means causes each of said active periods of said plural power transistors to become larger than the period of 360/Q electrical degrees,
said switching operation means produces a high-frequency switching pulse signal which responds with said command signal and switches said at least one power transistor responding with said switching pulse signal,
and
said phase detecting means includes:
slant producing means for producing a slant voltage signal at a terminal of a capacitor, said slant voltage signal responding intermittently with a voltage difference between one of the power supplying terminal voltages and the common terminal voltage of said Q-phase windings during sampling periods and having substantially a voltage slant during at least one of the rest periods except said sampling periods, and
phase pulse producing means for producing said phase pulse signal responding with said slant voltage signal.
With this configuration, the switching operation means cause the power transistors of the power supplying means to perform high-frequency switching. Hence, the power losses of the power transistors of the power supplying means are reduced remarkably, and heat generation at the disk drive apparatus is reduced significantly. In addition, the activation operation means control the active periods of the power transistors responding with the terminal voltages of the windings and cause the rotor to rotate in a predetermined direction. Therefore, no position sensor is necessary, and the configuration of the disk drive apparatus is simplified. Furthermore, the active periods of the power transistors are set so as to be larger than the period of an electrical angle of 360/Q degrees, whereby two of the power transistors are activated simultaneously during the alteration of current paths. Hence, the alteration of the current paths becomes smooth, and the pulsation of the generated drive force becomes small, thereby reducing vibration and acoustic noise of the disk remarkably. Still further, the slant voltage signal at the terminal (or across the terminals) of the single capacitor intermittently responds with the voltage difference between one of the power supplying terminal voltages and the common terminal voltage of the Q-phase windings during the sampling periods. The slant voltage signal has the voltage slant during at least one of the rest periods other than the sampling periods. As a result, it is possible to produce accurately the slant voltage signal which nearly corresponds to the voltage difference between one of the power supplying terminal voltages and the common terminal voltage. The phase detecting means selects one of the power supplying terminal voltages responding with the operation state of the activation operation means, for example. Since the slant voltage signal intermittently responds with the voltage difference between one of the power supplying terminal voltages and the common terminal voltage, the slant producing means can produce the slant voltage signal having an accurate voltage slant across the terminals of the single capacitor. Since the phase pulse signal responds with the slant voltage signal, the phase pulse signal is free from the influence of the switching of the power transistors. Therefore the phase pulse signal changes at accurate timing. The commanding means produces the command signal responding with the rotational speed of the rotor by using the phase pulse signal. The switching operation means causes at least one of the power transistors to perform high-frequency switching responding with the command signal. Hence, the rotational speed of the disk can be controlled accurately, thereby improving reliability during recording and/or reproduction. As a result, a disk drive apparatus with low power consumption, low temperature increase, low disk vibration and low disk noise, suited for recording and/or reproduction on a high-density disk can be realized at low cost.
A disk drive apparatus in accordance with further aspect of the present invention comprises:
head means for at least reproducing a signal from a disk or recording a signal on said disk;
processing means for at least processing an output signal from said head means and outputting a reproduced signal, or processing a signal and outputting a recording signal into said head means;
a rotor, having a field part which generates field fluxes, for driving directly said disk;
Q-phase windings (Q is an integer of 3 or more);
voltage supplying means, including two output terminals, for supplying a DC voltage;
power supplying means having plural power transistors, said plural power transistors supplying said Q-phase windings with bi-directional currents from said voltage supplying means;
phase detecting means for producing a phase pulse signal which responds with terminal voltages of said Q-phase windings;
activation operation means for controlling active periods of said plural power transistors responding with terminal voltages of said Q-phase windings;
commanding means for producing a command signal which responds with said phase pulse signal of said phase detecting means; and
switching operation means for causing at least one power transistor among said plural power transistors to perform high-frequency switching responding with said command signal;
and that
said activation operation means causes each of said active periods of said plural power transistors to become larger than the period of 360/Q electrical degrees,
said switching operation means produces a high-frequency switching pulse signal which responds with said command signal and switches said at least one power transistor responding with said switching pulse signal,
and
said phase detecting means includes:
slant producing means for producing a first voltage signal at a terminal of a first capacitor which intermittently responds with one of the power supplying terminal voltages of said Q-phase winding means, and producing a second voltage signal at a terminal of a second capacitor which intermittently responds with the common terminal voltage of said Q-phase windings during sampling periods and has substantially a voltage slant during at least one of the rest periods except said sampling periods,
and
phase pulse producing means for producing said phase pulse signal by comparing said first voltage signal with said second voltage signal.
With this configuration, the switching operation means cause the power transistors of the power supplying means to perform high-frequency switching. Hence, the power losses of the power transistors of the power supplying means are reduced remarkably, and heat generation at the disk drive apparatus is reduced significantly. In addition, the activation operation means control the active periods of the power transistors responding with the terminal voltages of the windings and cause the rotor to rotate in a predetermined direction. Therefore, no position sensor is necessary, and the configuration of the disk drive apparatus is simplified. Furthermore, the active periods of the power transistors are set so as to be larger than the period of an electrical angle of 360/Q degrees, whereby two of the power transistors are activated simultaneously during the alteration of current paths. Hence, the alteration of the current paths, becomes smooth, and the pulsation of the generated drive force becomes small, thereby reducing vibration and acoustic noise of the disk remarkably. Still further, the first voltage signal intermittently responds with one of the power supplying terminal voltages of the Q-phase windings. The second voltage signal intermittently responds with the common terminal voltage of the Q-phase windings during the sampling periods and has the voltage slant during at least one of the rest periods other than the sampling periods. The phase detecting means selects one of the power supplying terminal voltages responding with the operation state of the activation operation means, for example. Since the second voltage signal having the voltage slant responds with the common terminal voltage, the second voltage signal has a relatively intermediate level. It is thus easy to add the accurate voltage slant to the second voltage signal. Since the phase pulse signal responds with the comparison result between the first voltage signal and the second voltage signal, the phase pulse signal is free from the influence of the switching of the power transistors. Therefore the phase pulse signal changes at accurate timing. The commanding means produces the command signal responding with the rotational speed of the rotor by using the phase pulse signal. The switching operation means causes at least one of the power transistors to perform high-frequency switching responding with the command signal. Hence, the rotational speed of the disk can be controlled accurately, thereby improving reliability during recording and/or reproduction. As a result, a disk drive apparatus with low power consumption, low temperature increase, low disk vibration and low disk noise, suited for recording and/or reproduction on a high-density disk, can be realized at low cost.
These and other configurations and operations will be described in detail in the explanations of embodiments.